Drug interactions
Chloral hydrate + Promethazine
Severity: Major
Chloral hydrate and Promethazine: major interaction.
Last updated Sources: US FDA label
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Both agents depress the CNS, so together they may cause excessive sedation, hypotension and respiratory depression. This is particularly relevant in children and elderly patients.
What this interaction means in plain words
Chloral hydrate and Promethazine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Chloral hydrate belongs to Central Nervous System; Promethazine belongs to Respiratory.
Why it happens
Additive central nervous system depression.
What to do
Avoid the combination where possible, especially in children; if used, reduce doses and monitor sedation level and respiration.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Promethazine
- Cabergoline + Promethazine Contraindicated
- Dopamine + Promethazine Contraindicated
- Ibutilide + Promethazine Contraindicated
- Pimozide + Promethazine Contraindicated
- Promethazine + Thioridazine Contraindicated
- Alfentanil + Promethazine Major
Other interactions of Chloral hydrate
- Calcium / magnesium / potassium / sodium oxybates + Chloral hydrate Contraindicated
- Chloral hydrate + Sodium oxybate Contraindicated
- Alfentanil + Chloral hydrate Major
- Alprazolam + Chloral hydrate Major
- Amobarbital + Chloral hydrate Major
- Belladonna and opium + Chloral hydrate Major
Frequently asked questions
Can I take Chloral hydrate with Promethazine?
MediHelp rates the interaction as major. Chloral hydrate and Promethazine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Both agents depress the CNS, so together they may cause excessive sedation, hypotension and respiratory depression. This is particularly relevant in children and elderly patients.
How serious is the interaction between Chloral hydrate and Promethazine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination where possible, especially in children; if used, reduce doses and monitor sedation level and respiration.
What other medicines interact with Promethazine?
MediHelp also lists interactions of Promethazine with, for example, Cabergoline, Dopamine, Ibutilide. The full list is on the Promethazine page.
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